Tapping head for punch press

ABSTRACT

A unitized tapping head is incorporated into the turret of a multiple-tool punch press. The tapping head includes a unique replaceable cartridge which houses a tap and a feed lead screw. A self-contained drive unit rotates the cartridge to advance the tap at the same lead as the threads on the feed lead screw. The cartridge is held only by a simple spring clip and thus is easily replaced with the same or a different combination tap and corresponding feed lead screw.

United States Patent [191 Daniels [451 Jan. 29, 1974 TAPPING HEAD FORPUNCH PRESS [75] Inventor: Dennis Daniels, Bellevue, Wash.

[73] Assignee: U.S. Amada, Ltd., Seattle, Wash.

[22] Filed: Sept. 13, 1971 [21] Appl. No.: 179,952

[52] U.S. Cl 408/130, 408/3, 408/35, 408/126, 408/125, 408/137, 10/139 R[51] Int. Cl B23b 47/04, B23b 47/18 [58] Field of Search... 408/125,126, 130, 135, 137, 408/129, 124, 3, 35; 10/129 R, 139 R, 105; 29/36 56]References Cited UNITED STATES PATENTS 3,162,873 12/1964 Ohmei 10/139 RX 7/1957 Krahnke 11/1955 Perlotto 7/1915 Gladwin Primary Examiner-GilWeidenfeld Attorney, Agent, or FirmRichard W. Seed et a1.

[ 5 7] ABSTRACT A unitized tapping head is incorporated into the turretof a multiple-tool punch press The tapping head includes a uniquereplaceable cartridge which houses a tap and a feed lead screw. Aself-contained drive unit rotates the cartridge to advance the tap atthe same lead as the threads on the feed lead screw. The cartridge isheld only by a simple spring clip and thus is easily replaced with thesame or a different combination tap and corresponding feed lead screw.

14 Claims, 8 Drawing Figures PAIENIED JAN 2 9 I974 SHEET 1 0F 2 PEG 3DENNlS DANIELS INVENTOR.

E QL. 3

PATENIEI] JAN 2 91974 saw 2 0F 2 N.O. I LS2 FIG 6 -mLlRi DENNIS DANIELSINVENTOR ATTORNEYS TAPPING HEAD FOR PUNCH PRESS BACKGROUND OF THEINVENTION 1. Field of the Invention This invention pertains to punchpresses and more particularly to a unitized tapping head for use inpunch presses and a unique replaceable cartridge for housing a tap and acorresponding lead feed screw.

2. Description of the Prior Art I It is a customary practice in thefabrication of metal forms to punch holes in the material andsubsequently thread various of these holes by tapping them.I-Ieretofore, the punching operation has been automated to aconsiderable extent with the position of the workpiece beingautomatically positioned by a numerical control (N.C.) device. Thetapping operation, however, has not been adequately automated and thushas been difficult and time consuming. In the past holes have beentapped by manually positioning the workpiece beneath a separate tappingrig or drill press. Another technique has been to attach a tapping rigor rigs to the frame of the punch press laterally of the punch and usingthe same numerical control device for positioning the workpiece relativeto the punching tool, the workpiece would also be positioned relative tothe tapping rigs. This latter technique presented several problems.First, the worktable for supporting the workpiece had to be extended toprovide for positioning the workpiece laterally of the punch. Secondly,a separate independent numerical control program had to be utilized withthe NC. device in order to effect positioning of the workpiece relativeto the tapping rig rather than the punch. Thirdly, the cost of aseparate independent tapping rig had to be added to the basic cost ofthe punching machine SUMMARY OF THE INVENTION It is an object of thisinvention to provide a unitized tapping head for use in a punch press.

It is another object to provide a unitized tapping head for use in amultiple-tool turret type punch press.

It is another object of this invention to provide a replaceablecartridge having a self-feeding tap synchronized with a proper feed leadscrew.

It is another object of this invention to provide a unitized tappinghead in combination with a numerically controlled punch press in whichthe tap is automatically lowered and raised'as a part of the automaticsequencing of the punch press.

It is another object of this invention to provide a compact drive foruse in a unitized tapping head.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic perspectiveillustrating a typical numerically controlled punch press embodying aunitized tapping head.

FIG. 2 is a vertical section of the preferred tapping head embodiment.

FIG. 4 is a plan illustrating a portion of the unique cartridge used inthe tapping head.

FIG. 5 is a fragmentary section of the tapping head illustrating thepreferred cartridge of the invention.

FIG. 6 is a typical circuit diagram for automatically advancing andretracting the tap.

FIG. 3 is a section taken along the line 3-3 of FIG.

FIG. 7 is a section of a modified form of tapping head utilizing ahydraulic drive.

FIG. 8 is a section taken along the line 88 of FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As best shown in FIG. 1 anumerically controlled punch press 10 is shown illustrated with amultiple-tool rotary turret l2 and a work supporting table 14. The worksupporting table is provided with conventional workpiece positioningmeans 16 which are controlled by a numerical control (N.C.) device 18.As is well known, the NC. device operates to position the workpiece andthe rotary turret according to a prearranged program so that a desiredoperation takes place on the workpiece and then repositions either therotary turret or the workpiece or both to perform the next desiredoperation. Secured in the rotary turret, in the same manner as any ofthe other tools, is a unitized tapping head 20 embodying the principlesof the invention. Al though the tapping head is uniquely applicable fora multiple-tool turret type punch press, it is also advantageouslyemployed in a conventional single stationary tool holder type punchpress in which the tools are interchangeably' employed.

As best shown in FIGS. 2 and 3 the unitized tapping head 20 includes abase 22 which is locked into the turret 12 by any suitable means. Thebase houses a self contained conventional pneumatic or electrical motor24 which may be operated in the forward or reverse directions and has aself-energizing brake which stops the output shaft of the motor prior toinitiating motion in the opposite direction. For the purpose of thisdescription an electrical motor will be described; however theprinciples are equally applicable to a pneumatic motor. The motor 24 issecured to the base by suitable means and is provided with an outputshaft 26 that is coupled to worm gear 28. The worm gear 28 meshes with apinion 30 which may be rotated by the worm gear either in the clockwiseor counterclockwise direction. The pinion gear is mounted for rotationin the base in suitable bearings 32 and is provided with an internalaxial bore 34. The bore 34 is provided with axial grooves 36 for apurpose to be described.

The tapping head 20 is provided with a unique replaceable tappingcartridge 38. The tapping cartridge includes a core member 40 having anupper axial bore 42, a lower axial bore 44, anda plurality of splines 46which slidably engage within the grooves 36 of the pinion gear 30.Removably secured in the bore 44 is a conventional tap 48 having acutting thread of a prescribed lead. As is well known in the art, thetap must be simultaneously rotated and advanced axially into the bore ata prescribed rate so that the proper lead is provided in the threadbeing cut in the bore.

The desired thread lead is obtained by a feed lead screw 50 havingthreads at the same lead as the cutting edges of the tap 48. The leadscrew is threaded into a bushing 52 that is rigidly secured to the coremember 40. The lead screw is fixed against rotation in the base by a capscrew 54 that is seated partially in a notch in the head of the leadscrew and partially in a complemetary notch in a latch plate 56 that issecured to the base 22. As is readily apparent, rotation of the coremember 40 through rotation of the pinion 30 will cause the bushing andthus the core member to thread itself downwardly on the fixed lead screw50, thus advancing the tap 48 at the desired lead into the workpieceW.

It is a particularly advantageous feature of this tapping head that thecartridge 38 is easily removable from the tapping head to be exchangedwith either an identical cartridge or one having a feed screw and tap ofa different lead configuration. For this purpose the head of the leadscrew 50 is provided with a circumferential groove 58 that is alignedwith a groove 60 in the latch plate 56 when the cartridge is inserted inthe tapping head. A conventional spring clip 62 is shown in FIG. 4 asbeing expanded to fit partially within the groove 58 and partiallywithin the groove 60 so that the cartridge is held locked within thelatch plate 56. The groove 58 is of a smaller internal diameter than thebore in the latch plate so that by pressing the ends of the spring cliptogether the circular portionof the clip is retracted entirely withinthe groove 58 and the cartridge can then be removed from the tappinghead. Installation of a new cartridge is accomplished in the reversemanner by compressing the spring clip 62 inserting the cartridge andthen allowing the spring clip to expand to again engage the groove 60.It is, of course, quite apparent that this substitution can beaccomplished quickly and without any special tools.

It is another unique feature of this tapping head that it automaticallysenses its position relative to the depth of the tap into the boreof theworkpiece so that reversal of the drive motor and retraction of the feedscrew may take place automatically and thus become a part of the programof the numerical control device. For this purpose the core member isprovided with a cam slot 64 in which a spring biased switch arm 66 isengaged. Movement of the core member axially causes the switch arm 66 toride out of the cam slot and engage a switch contact LS2. Similarly acam slot 68 is engaged by a switch arm 70 which engages a contact LS1when the switch arm 70 is within the cam slot 68. Contacts LS1 and LS2are incorporated into the circuit shown in FIG. 6. As is best shown inFIGS. 2 and 6 when the tap is retracted, the contact LS2 is opened withswitch arm 66 seated in cam slot 64. At the same time contact LS1 isalso opened with the switch arm 70 riding out of the cam slot 68.Closing of switch 72 either manually or from a signal from the NC.device 18 as part of a predetermined program energizes relay R1 throughnormally closed contact R2. Relay contacts R1 are closed to lock-in thecircuit through relay R1. Closi-ng contacts R1 in the motor circuit willinitiate forward operation of the motor so that the pinion 30 is rotatedin the direction necessary to advance the tap 48. At the moment the coremember 40 is advanced the switch arm 70 enters the cam slot 68 thusclosing contact LS1. Since LS2 remains open, however, no change occursin the circuit. When the core member has advanced to the desireddistance such that the tap has threaded the hole in the workpiece, theswitch arm 66 will ride out of the cam slot 64 closing contact LS2 thuscompleting 'the circuit to relay R2. Contacts R2 are closed to lock-inthe relay R2 and to open the contacts to the relay R1 whilesimultaneously closing the contacts R2 to the reverse motor circuit. Asis understood in motors of this type, the motor will first brake itselfto a. stop and will then begin operation in the reverse directionthreading the core member 40 upwardly out of the workpiece. When thecore member reaches its uppermost position as shown in FIG. 2,

contact LS1 will again be opened thus opening the circuit to relay R2.All of the contacts in the motor circuit will then be opened and themotor will brake itself to a stop ready for the next signal to beginoperation. If part of a prearranged program, opening LS1 will signal tothe NC. device to sequence to the next operation in the program. Y

The modification shown in FIGS. 7 and 8 employs a cartridge 38 basicallyidentical to that shown in the preferred embodiments. Base 22a ismodified slightly so that the cartridge 38 is directly coupled to thebase member by a set screw 54a which seats in complementary notches inthe head of the lead feed screw 50 and the base member 22a. In themodification a pinion 80, also connected to the body member by a splineand groove connection as in the preferred embodiment, is drivinglyengaged by a pair of hydraulically driven gears 82. Obviously a singlegear could suffice, but the double gear arrangement advantageouslyincreases the torque to the pinion. The gears 82 are journaled in thebase member 20 and are simultaneously driven by fluid entering ports 84for rotation of the pinion in one direction or fluid entering ports 86and exiting ports 84 for rotation in the opposite direction. Operationof the modification is basically the same as that of the preferredembodiment. The numerical control device will send a signal to the fluidsource to direct fluid into either the ports 84 or 86 and upon receiptof the various signals from switches LS1 and LS2 the motor will bebrought to a stop and then reversed.

While preferred forms of the invention have been illustrated anddescribed, it should be understood that variations and furthermodifications will be apparent to one skilled in the art withoutdeparting from the principles of the invention. Accordingly, theinvention is to be limited only by a literal interpretation of theclaims appended hereto.

I claim 1. In a machine having a tapping head and means for supporting aworkpiece opposite said tapping head; said tapping head comprising meansfor removably holding a tap for rotational and axial movement; and drivemeans for simultaneously rotating and advancing said tap into aworkpiece positioned on said workpiece supporting means; said tappinghead including a hollow base secured to said tool holding means; saidmeans for removably holding the tap for rotational and axial movementincluding a cartridge releasably retained in said base and removable asa unit in a direction away from said workpiece supporting means; saidcartridge including a core member having an outer end, said tap beingsecured in said outer end of said core member, a feed lead screw havinga longitudinal axis concentric with the longitudinal axis of said tap,said tap and said lead screw having threads of substantially identicallead; and said drive means including force transmitting means secured insaid base for advancing the core member relative to the lead screw andallowing said cartridge to be slid axially out of said base as a unitaway from said workpiece for replacement of said feed lead screw andsaid tap.

2. The apparatus of claim 1 said tool holding means including a multipletool turret having an upper plate provided with circumferentially spacedtool holding opening, said tapping head secured within one of saidopenings, and means for positioning the turret to place a desiredopening over a desired location on a workpiece in the same manner as anyother tool on the turret.

3. The apparatus of claim 2, said drive means including means forautomatically stopping the movement of the core member when the tap isfull-out and full-in.

4. The apparatus of claim 1, said drive means including a motor having aworm gear, a pinion gear driven from said worm gear, and means foroperatively connecting said pinion gear to said tap for rotating the tapwhile allowing relative axial movement.

5. A tapping head for a machine having a workpiece supporting means,comprising means for removably holding a tap for rotational and axialmovement, and drive means for simultaneously rotating and advancing saidtap for moving said tap into a workpiece positioned on said workpiecesupporting means, said drive means including a motor having a worm gear,a pinion gear driven from said worm gear, and means for operativelyconnecting said pinion gear to said tap for rotat' ing the tap whileallowing relative axial movement, said means for operatively connectingsaid pinion gear with said tap including a core member having a splineand groove connection for allowing axial movement of the core whilebeing rotated by said pinion gear, a feed lead screw secured againstrotation in said tapping head, a bushing secured to said core member andthreadably engaging said lead screw whereby rotation of the pinionscrews the bushing and thus the core member axially, said tap beingsecured within said core member and extending downwardly therefrom forcutting a thread in said workpiece when the tap is rotated and advanced.

6. A tapping head for a machine having a workpiece supporting means,comprising a means for removably holding a tap for rotational and axialmovement, and drive means for simultaneously rotating and advancing saidtap for moving said tap into a workpiece positioned on said workpiecesupporting means, said drive means including an hydraulic motor having afluid inlet and outlet and at least one pair of fluid driven gearsbetween said inlet and outlet, one of said gears operativelyinterconnected with the tap for rotating the tap and moving the tapaxially.

7. The apparatus of claim 6, said means for operatively connecting saidgear with said tap including a core member having a spline and grooveinterconnection with said gear for allowing axial movement of said coremember as it is rotated, a feed lead screw secured against rotation insaid tapping head, a bushing secured to said core member and threadablyengaging said feed lead screw whereby rotation of the gear screws thecore member axially, said tap being secured within said core member andextending downwardly therefrom for cutting a thread in said workpiece atthe same lead as the feed lead screw when the tap is rotated andadvanced.

8. The apparatus of claim 3, said punching machine having a numericalcontrol device for positioning the turret and workpiece and actuatingthe tapping head according to a prearranged program, said control deviceautomatically actuating the drive means for tapping the workpiece sothat the workpiece is tapped with the same program and at the sameposition beneath the turret as any other tool on the turret.

9. A tapping head for use in a machine suitable for tapping holes in aworkpiece supported on a workpiece supporting means comprising a hollowbase, a cartridge means for removably mounting said cartridge in saidbase, drive means for rotating said cartridge, said cartridge includinga tap, a feed lead screw, means interconnecting said tap and feed leadscrew wherein rotation of said cartridge simultaneously rotates andaxially moves said tap at the same rate as the lead of said feed leadscrew whereby a change of tap size is effected by replacing the entirecartridge with a cartridge having the new tap size and a new feed leadscrew corresponding to the new tap size so that the tap and the leadrate are always properly correlated, said cartridge being removable fromsaid base and said drive means within said base in a direction away fromsaid workpiece supporting means for ease of replacement of said tap andfeed lead screw.

10. The tapping head of claim 9, said cartridge further including a coremember having a spline and groove connection with said drive means, thetap secured in one end of said core member, an axial bore in the otherend of said core member, a bushing in said axial bore and secured tosaid core member, said feed lead screw threadably engaging said bushing,means for securing said feed lead screw against rotation in said basewhereby rotation of said core member axially advances the bushing andthus the core member along said feed lead screw at the desired lead.

11. The tapping head of claim 7, said means for removably mounting saidcartridge in said base including a latch plate secured to the base andhaving a central bore, a groove around the periphery of said bore, saidfeed lead screw having a head provided with a circumferential groove,and a spring clip compressible entirely within said groove in said headfor permitting withdrawal of said cartridge from said base andexpandable to partially seat in said groove in said head and said groovein central bore of said latch plate for releasably locking saidcartridge in said base.

12. The apparatus of claim 1, said drive means in cluding means forautomatically stopping movement of the core member when the tap isfull-out and full-in.

13. The tapping head of claim 9, said means for removably mounting saidcartridge in said base including a latch plate secured to the base andhaving a central bore, and means releasably securing said cartridge tosaid latch plate, said cartridge being removable from said base throughsaid central bore of said latch plate.

14. The tapping head of claim 13, a groove around the periphery of saidcentral bore of said latch plate, said feed lead screw having a headprovided with a circumferential groove, and a spring clip compressibleentirely within said groove in said head for permitting withdrawal ofsaid cartridge from said base and expandable to partially seat in saidgroove in said head and said groove in said central bore of said latchplate for releasably locking said cartridge in said base.

1. In a machine having a tapping head and means for supporting aworkpiece opposite said tapping head; said tapping head comprising meansfor removably holding a tap for rotational and axial movement; and drivemeans for simultaneously rotating and advancing said tap into aworkpiece positioned on said workpiece supporting means; said tappinghead including a hollow base secured to said tool holding means; saidmeans for removably holding the tap for rotational and axial movementincluding a cartridge releasably retained in said base and removable asa unit in a direction away from said workpiece supporting means; saidcartridge including a core member having an outer end, said tap beingsecured in said outer end of said core member, a feed lead screw havinga longitudinal axis concentric with the longitudinal axis of said tap,said tap and said lead screw having threads of substantially identicallead; and said drive means including force transmitting means secured insaid base for advancing the core member relative to the lead screw andallowing said cartridge to be slid axially out of said base as a unitaway from said workpiece for replacement of said feed lead screw andsaid tap.
 2. The apparatus of claim 1 said tool holding means includinga multiple tool turret having an upper plate provided withcircumferentially spaced tool holding opening, said tapping head securedwithin one of said openings, and means for positioning the turret toplace a desired opening over a desired location on a workpiece in thesame manner as any other tool on the turret.
 3. The apparatus of claim2, said drive means including means for automatically stopping themovement of the core member when the tap is full-out and full-in.
 4. Theapparatus of claim 1, said drive means including a motor having a wormgear, a pinion gear driven from said worm gear, and means foroperatively connecting said pinion gear to said tap for rotating the tapwhile allowing relative axial movement.
 5. A tapping head for a machinehaving a workpiece supporting means, comprising means for removablyholding a tap for rotational and axial movement, and drive means forsimultaneously rotating and advancing said tap for moving said tap intoa workpiece positioned on said workpiece supporting means, said drivemeans including a motor having a worm gear, a pinion gear driven fromsaid worm gear, and means for operatively connecting said pinion gear tosaid tap for rotating the tap while allowing relative axial movement,said means for operatively connecting said pinion gear with said tapincluding a core member having a spline and groove connection forallowing axial movement of the core while being rotated by said piniongear, a feed lead screw secured against rotation in said tapping head, abushing secured to said core member and threadably engaging said leadscrew whereby rotation of the pinion screws the bushing and thus thEcore member axially, said tap being secured within said core member andextending downwardly therefrom for cutting a thread in said workpiecewhen the tap is rotated and advanced.
 6. A tapping head for a machinehaving a workpiece supporting means, comprising a means for removablyholding a tap for rotational and axial movement, and drive means forsimultaneously rotating and advancing said tap for moving said tap intoa workpiece positioned on said workpiece supporting means, said drivemeans including an hydraulic motor having a fluid inlet and outlet andat least one pair of fluid driven gears between said inlet and outlet,one of said gears operatively interconnected with the tap for rotatingthe tap and moving the tap axially.
 7. The apparatus of claim 6, saidmeans for operatively connecting said gear with said tap including acore member having a spline and groove interconnection with said gearfor allowing axial movement of said core member as it is rotated, a feedlead screw secured against rotation in said tapping head, a bushingsecured to said core member and threadably engaging said feed lead screwwhereby rotation of the gear screws the core member axially, said tapbeing secured within said core member and extending downwardly therefromfor cutting a thread in said workpiece at the same lead as the feed leadscrew when the tap is rotated and advanced.
 8. The apparatus of claim 3,said punching machine having a numerical control device for positioningthe turret and workpiece and actuating the tapping head according to aprearranged program, said control device automatically actuating thedrive means for tapping the workpiece so that the workpiece is tappedwith the same program and at the same position beneath the turret as anyother tool on the turret.
 9. A tapping head for use in a machinesuitable for tapping holes in a workpiece supported on a workpiecesupporting means comprising a hollow base, a cartridge means forremovably mounting said cartridge in said base, drive means for rotatingsaid cartridge, said cartridge including a tap, a feed lead screw, meansinterconnecting said tap and feed lead screw wherein rotation of saidcartridge simultaneously rotates and axially moves said tap at the samerate as the lead of said feed lead screw whereby a change of tap size iseffected by replacing the entire cartridge with a cartridge having thenew tap size and a new feed lead screw corresponding to the new tap sizeso that the tap and the lead rate are always properly correlated, saidcartridge being removable from said base and said drive means withinsaid base in a direction away from said workpiece supporting means forease of replacement of said tap and feed lead screw.
 10. The tappinghead of claim 9, said cartridge further including a core member having aspline and groove connection with said drive means, the tap secured inone end of said core member, an axial bore in the other end of said coremember, a bushing in said axial bore and secured to said core member,said feed lead screw threadably engaging said bushing, means forsecuring said feed lead screw against rotation in said base wherebyrotation of said core member axially advances the bushing and thus thecore member along said feed lead screw at the desired lead.
 11. Thetapping head of claim 7, said means for removably mounting saidcartridge in said base including a latch plate secured to the base andhaving a central bore, a groove around the periphery of said bore, saidfeed lead screw having a head provided with a circumferential groove,and a spring clip compressible entirely within said groove in said headfor permitting withdrawal of said cartridge from said base andexpandable to partially seat in said groove in said head and said groovein central bore of said latch plate for releasably locking saidcartridge in said base.
 12. The apparatus of claim 1, said drive meansincluding means for automatically stopping movement of the core memberwhen the tap is full-out and full-in.
 13. The tapping head of claim 9,said means for removably mounting said cartridge in said base includinga latch plate secured to the base and having a central bore, and meansreleasably securing said cartridge to said latch plate, said cartridgebeing removable from said base through said central bore of said latchplate.
 14. The tapping head of claim 13, a groove around the peripheryof said central bore of said latch plate, said feed lead screw having ahead provided with a circumferential groove, and a spring clipcompressible entirely within said groove in said head for permittingwithdrawal of said cartridge from said base and expandable to partiallyseat in said groove in said head and said groove in said central bore ofsaid latch plate for releasably locking said cartridge in said base.